This invention relates to a fork lift truck having a mast assembly supported by a parallelogram linkage and more particularly to the mechanism for adjusting the tilt angle of the fork carriage.
A fork lift truck typically has a stationary upright secured to the forward end of the vehicle, one or more inner uprights slidably disposed in telescopic fashion relative to the stationary upright and a fork carriage mounted for vertical movement relative to the innermost upright. A vertically arranged hydraulic jack is normally centrally located within the innermost upright and cooperates with a chain reeving arrangement for raising and lowering the inner uprights and the fork carriage either sequentially or simultaneously, or a combination of both. One of the problems associated with such a lift truck is that the vertical uprights, hydraulic jack and chain reeving greatly obstruct the forward visibility of the operator. This contributes to operator fatigue since he is constantly looking through the mast assembly and is continually leaning to one side or the other in an effort to see around the components of the mast assembly to watch where he is going. Another problem encountered is that to provide maximum lift height with a minimum number of uprights, the uprights are relatively tall and the vertical height prevents passage of the fork lift truck through many doorways. A desirable feature commonly provided on fork lift trucks is that of being able to tilt the mast assembly or fork carriage rearwardly to elevate the forward tips of the fork for improved load retention when maneuvering the lift truck.